X-ray tube



f AUNITED STATES Patented Pearl, 1939 vPATENT OFFICE X-RAY TUBE Adrianus Verhoeff, Eindhoven, Netherlandaas;

signor to N. V. lPhilips Gloeilampenfabrieken, Eindhoven, Netherlands Application July 17, 1936, Serial No. 91,237

In Germany Allgust 12, 1935 Claims.

My invention relates to X-ray tubes and more particularly to X-ray tubes for treating cavities or for contact therapy.

X`ray tubes used for the above purposes must structions, however, have the drawback that the terminal piece increases the diameter of the asl5 sembly, and greatly impedes the introduction of the tube into the cavities to be irradiated. In additionA with the X-ray tube used for this purpose,

a `large amount of the heat developed in the anode is transmitted toward the cable end of the tube, and deleteriously affects the insulating material of the cable.

@ne object of my invention is to provide an X-ray device comprising Yan X-ray tube and a supply cable which are mechanicallyand electrically connected without the use of additional insulating terminal pieces.

A further object of my invention is to provide an X-ray device in which the outer`suriace of the X-ray tube forms a continuation of the suriace'of the supply cable.

A still further object i's to reduce the amount of heat transmitted toward the cable end of the tube.

A- In accordance with thel invention, I provide a high-tension supply cable at one end with a c avity into which one end of an X-ray tube snugly fits, and mechanically and electrically connect the tube and cable without the use of additional insulating terminal members.

40 In order to permit the X-ray tube and cable to bereadily handled for irradiating cavities, I make the 'diameter of the projecting portion of the tube substantially the same as that of the cable, whereby the tube and cable form a substantially cylindrical body. 'v I 'To prevent the body to be irradiated from coming into contact with members'of the assem# y bly under high-tension I form the projecting portion of the tube envelope as a metal cylinder, and

connect same to ground. i v

' Furthermore, to assure rigidity of the assembly and also to prevent rupture ofthe glass envelope portion by excessive bending, I surround the metal cylinder and the adjacent portion of be comparatively small, and it is exceedingly dif- (Cl. 25o- 142) serves to ground the metal cylinder by connecting same to a grounded -layer provided on the cable.

For electrically connecting the conductor of the cable to the high-tension electrode of the X-ray tube, as well as for mechanically securing 5 the tube to the cable, I provide on the end of the glass portion extending into the cable a metal supporting member carrying the high-tension electrode, and cooperating with a contact member permanently secured to the conductor of the 10 cable. This metal member may also serve for 'exhausting the X--ray tube and may be closed after exhaustion with a glass press which is protected by the cable.

To reduce the amount of heat transmitted to- 15 wardsfthe cable end of the tube, I support the anode from the envelope by means of a supporting member of low heat conductivity, or the metal supporting member may be interrupted by 'a thermal insulator, such as a glass tube which oi 20 course must be shunted, -for instance by a conductive coating, in vorder to allow passage 4oi? curl rent to the anode. t

In order that my invention may be clearly ung derstood and readily carried into eifect, I shall 25 describe same more fully withreference to the accompanying drawing, inwhich:

Figure 1 is a sectional view of an X-ray'tube device according to the invention, and

Fig. 2 isa sectional View of an X-ray tube ac- 30 cording to the invention. y 4

The X-ray tube shown in Fig. 1 has an evacuated envelope comprising a cylindrical metal portion I and a tapering or funnel-shaped glass portion 2 sealed together at 3. Closing the upper 35 end of cylinder I and sealed thereto atl is a glass window 5 for the exit of the X-rays. Sealed at 30 to the lower end oi the glass portion 2 and extending downwardly into a tapering portion 2 I,l

land also extending upwardly, is a metal tube 6 to 40 the upper end of zwhich is sealed a glass tube 9. To the upper end of tubes is sealed a metal tube '8 provided with an aperture 24. The lower end of thetube 8 isprovided withl a glass tip 23 whereby The Xray tube is provided with a cylindrical shaped anode, 1, which may be of tungsten, supported from the metal tube 8 by a metal member I2 having an enlarged lower end II, which closes50 the end of tube 8. The member I2 and the glass tube 9 serve to reduce the amount of heat transmitted from the anode l to the end of the tube.` The member I2 is provided with a disc I3, for in stance of tungsten, which serves to prevent unl5 desirable rearward radiation of heat and thereby protects the seal 3 from being overheated by radiation from the anode. It also absorbs X-rays emanating in rearward direction.

To electrically connect tubes 6 and and thus to connect the anode to the tube 6, a thin metal coating III is provided over the surface of the glass tube 9 and is connected to the tubes 6 and 8. The coating I0 mayalso serve vas a protective resistance.

Above the anode 1 is a V-shaped cathode lament |4 supported at its apex by a central support l5 and at its ends by two lead-supports 3|; only one of the supports 3| being visible in Fig. 1. The support I5 is insulatingly secured to the metal tube I whereas the supports 3| pass in a vacuum-tight manner through glass beads 4,0 sealed in the tube I. One of the lead-supports 3| may be electricallyconnected to the metal cylinder I, in which case the tube is operated with a grounded cathode. However, there may also be a small potential difference in which case both of the leads 3| are insulated from ythe cylinder I and are connected to low-tension conductors .for the supply of the cathode heating current.

High-tension current issupplied to the X-ray tube through a high-tension cable having a hollow flexible conductor I6, for example of Wire netting, within which is a core 26 of insulating material, for instance rubber. Surrounding the conductor I6 is an insulating body I1, for instance of rubber, whose end is provided with a cavity snugly iitting the funnel-shaped glass portion 2.

An outer metal tube I8 surrounds the X-ray tube and a portion of the cable and thereby provides suiilcient rigidity to ,prevent damaging of 'Ihere is also a small space'between the tubes I and I8 so that the wires 32 connected to the leads 3| may be insulatingly enclosed in this space and brought out at 35.

Secured to the lower end of tube I8 is a metal connecting piece I9 electrically connecting tube I 6 to a grounded layer 20 of Wire netting covering the cable.

'I'he tube I8 is centered in the cylinder I by means of a plurality of elastic members, for example three in number, one of which is shown at 33, these members being secured to tube |8 at 34.

The electrical connection between the anode 1 and the conductor I6 is effected by means 'of a metal cylindrical member 25 detachably secured,

for example by screw threads, tothe portion 2| vandpermanently secured to the cable at the bottom of the cavity. To secure the member 25 to the. cable so that it-will not become detached when removing the X-ray tube, the core 26 is bored and is expanded, for instance by a'central wedge shown as a wood screw 21, against the inner wall of the metal tube I6. In this manner the lower end of member 25 is brought into good electrical contact with the upper end ofconductor I6 and 'is also ,securely iixed so that it will not become loosened upon removal of the X-ray tube.

It will be noted that the assembly or the X-ray tube and cable has no radially-projecting parts and that the high-tension parts are not in contact with the open air. Due to this, the tube may be readily introduced into cavities of the body without the danger of electrical shocks; the device thus being particularly adapted for shortdistance treatment. Furthermore, it should be noted that the enclosed air space lying between the exhaust connection 23 and the screw 21 will cause no disturbing effect, as it is surrounded by the metal portion 25 which is under tension and therefore an electric iield cannot occur in this space. In order to avoid air pockets between the glass wall 2 and the rubber body I1, I apply a little insulating uid, such as ricinus oil to the outer surface of the glass portion 2 before putting it into the cable.

To facilitate handling of the device, a handle 29 is secured to connecting part I9 or it may be secured to the metal tube |8.

Fig. 2 shows a portion of an X-ray tube which is similar to that shown in Fig. 1 with the exception that the glass member 9 and metal member 6 are omitted and the bottom portion of the envelope is formed as a usual reentrant portion 42. To the re-entrant portion 42 is sealed a metal cylinder 48 whose upper end is closed by the projecting portion |I of the support I2. In this construction the tube, is exhausted at 43. A metal tube 44 serves for'the electrical connection of tube 48 with the conductor |6 of the cable. It is provided with a slit 45 for the passage of the exhaust stump 43. The upper end of tube 44 has a slightly enlarged diameter and is formed as a spring contact by means of slits 46, so that it bears on the inner wall of tube 48.

As stated above, the member I2 serves to reduce the amount of heat transferred to the lower portion of the tube and for this purpose is made of an electrically-conductive material of low heat conductivity, for instance chrome-iron, and/or is given a small cross-sectional area and made hollow. v

Similar to Fig. 1, a disc I3 of X-ray absorbing material, such as tungsten, servesl to prevent undesired radiation of X-rays. The'space 41 between the glass portion 42 and the rubber body |1 and between the reentrant glass por-tion and the tube 44 is iled up with an insulating ,substance, such as the material known under the name De Kothinsky cement.

4While I have described my invention in connection with specic examples and applications, I do not wish to be limited thereto, but desire the appended claims to be construed as broadly as permissible in view of the prior art.

l. An X-ray device comprising an X-ray tube havingl an envelope and electrodes, a exible high-tension supply cable having a conductor, and resilient high-tension insulation provided at one-,end with a cavity, a portion of said envelope snugly fitting into said cavity and being embraced by said insulation without radial intermediate spaces, the portion of the insulation receiving the envelope having substantially the -same outside diameter as the insulation covering the conductor, and means within said cavity for electrically and mechanically connecting said tube and cable.

2. An X-ray device comprising an X-ray tube having an envelope and electrodes, a high-tension supply cable having a conductor and highy tension insulation, said insulation being provided at one end with a cavity, a portion of said envelope snugly tting into said cavity without radial intermediate spaces, the portion of the tube envelope extending from the cable being substantially cylindrical and of substantially the same outside diameter as the insulation of the cable, and means Within the cavity for electrically and mechanically interconnecting 'said tube and cable.

3. An X-ray device comprising'an X-raytube having an envelope and electrodes, said envelope having a cylindrical metal portion and a portion of insulating material, a high-tension cable having a conductor and high-tension insulation, said insulation being provided at one end with a cavity, said insulating portion snugly fitting into said cavity Without radial intermediate spaces, means within said cavity for electrically and mechanically interconnecting said tube and cable, and a metal member closely surrounding said metal portion and the adjacent portion of the cable.

4. An X-ray device comprising an X- ray tube having an envelope and electrodes, said envelope having a tapering portion of insulating material, and a cylindrical metal portion surrounding one of -said electrodes, a metal member secured to said insulating portion and supporting the electrode surrounded by said metal portion, a highytension cable having a conductor and high-tension insulation and provided at one end with a cavity, said tapering portion snugly tting into said cavity, and means including said metal member electrically and mechanically interconnecting said tube and cable.

5. AnX-ray device comprising an X-ray tube having an envelope and electrodes, said envelope having a funnel-shaped portion of insulating material and a cylindrical metal portion surroundingone of said electrodes, a metal tube secured to said funnel-shaped portion and supporting the electrode surrounded by said metal portion, a high-tension cable having aconductor and high-tension insulation and provided at one end with a cavity, said funnel-shaped portion snugly fitting said cavity, means including said metal tube for electrically and mechanicallyinterconnecting said X-ray tube and cable, and a vitreous pump-connecting member closing the end of the metal tube.

6. An X-ray device comprising an X-ray tube having an envelope and electrodes, said envelope havingl a tapering portion of insulating material and a cylindrical metal portion surrounding one of said electrodes, a metal tube secured to said tapering portion and supporting the electrode surrounded by said metal portion, a high-tension cable having a conductor and high-tension insulation and provided at one end with a cavity, said tapering portion snugly fitting into said cavity, and means including said metal tube electically connecting said `conductor tothe electrode surrounded by said metal portion, said .means comprising a metal connecting member mounted at the bottom of the cavity and permanently secured to the conductor of the cable.

'7. An X-ray device comprising an X-ray tube having an envelope and electrodes, said envelopehaving a tapering portion of insulating material and a cylindrical metal portion surrounding one of said electrodes, a metal tube secured to said tapering portion and supporting the electrode surrounded by said metal portion, a high-tension cable having a hollow flexible conductor, hightension insulation, and a core of flexible insulating material Within said conductor, said cable being provided at one end with a cavity, said taperingportion snugly tting into said cavity, and means including said metal tube for connecting said conductor to the electrode surround- .ed by said metal portion, said means comprising a metal connecting member extending between said core and conductor, and means to expand the core against said member to secure same to the cable and to electrically connect same to the conductor in a permanent manner.

8. An X-ray device comprising an X-ray tube having an envelope, an anode and a cathode, said envelope having a tapering vitreous portion and a metal cylinder surrounding said anode, means to support said anode comprising a metal tube sealed to said vitreous portion and a connecting member of low thermal conductivity, a high-tension cable having a conductor andy high-tension insulation and provided at one end with a cavity, said vitreous portion snugly iitting into said cavity, and means including said metal tube and connecting member for electrically connecting the anode to the conductor and comprising a metal member permanently secured to said conductor and detachably secured to said metal tube.

9. An X-ray device comprising an X-ray tube having an envelope, an anode and a cathode, said envelope having a tapering vitreous portion and a metal cylinder surrounding said anode,

means to support said anode comprising a metal A tube sealed to saidrvitreous portion and a glass tube interrupting said metal tube and sealed thereto, an electric shunt across said glass tube,

a high-tension cable having a. conductor and hightension insulation and provided at one end with a cavity, saidy vitreous portion snugly fitting into said cavity, and means including said metal tube and connecting member for electrically connecting the anode to the conductor and comprising a metal member permanently secured to said conductor and detachably secured to said metal tube.

10. An X-ray device comprising an X-ray tube having an envelope, an anode and a cathode, said envelope having a tapering vitreous portion and a metal cylinder surrounding said anode, means to support said anode comprising a metal tube sealed to said yvitreous portion, and a glass tube interrupting said metal tube and sealed thereto, and a resistance in serie's With the anode and supported by said glass tube, a high-tension cable lhaving a conductor and high-tension insulation andprovided at one end with a cavity, said vitreous portion snugly fitting into said cavity, and means including said metal tube and connecting member for electrically connecting the anode to the conductor and comprising a metal member permanently secured to said conductor and detachably secured to said metal tube.

' ADRIANUS VERHOEFF. 

